import java.util.Scanner;

public class Exec06 {

    public static void main(String[] args) {
        // 计算 n 的阶乘
//        System.out.println(new Random().nextInt(39) + 1);
        Scanner sc = new Scanner(System.in);
        int number = sc.nextInt();
        // 记录最终的结果
        int result = 1;
        // 从 1 乘到它本身
        for (int i = 1; i <= number; i ++) {
            result *= i;
        }
        System.out.println("你要计算的" + number +"的阶乘是" + result);
    }
}
